Submersible dredging pump and shovel arrangement with suspension and towing means therefor

ABSTRACT

A submersible dredging pump and shovel arrangement comprising a compressed air pump and disintegrating and conveying shovels which are suspended and towed along a dredging trajectory, the pump comprising three cylinders arranged for being filled with the dredged material and pumping it in sequence by means of compressed air cyclically fed to the cylinders under the control of a distributor, each cylinder being connected to a corresponding dredging shovel having a front cutting edge, which in turn is provided with cutting knives inclined forwardly and downwardly so as to sink in the bed being dredged.

[ Oct. 22, 1974 United States Patent 1191 Faldi Gardner, 37/55 X 37/DIG. 8 37/7l X t e y l mm rfld SF [DO 667 999 HHH 5'2 11 263 23 0004 4002 333 Primary Examiner -Clifford Dv Crowder Attorney, Agent, or FirmKarl W. Flocks [76] Inventor: Giovanni Faldi, Via Forese Donati 27, Firenze, Italy Mar. 7, 1973 ABSTRACT [22] Filed:

A submersible dredging pump and shovel arrangement [211 App]. No.. 338,976 comprising a compressed air pump and disintegrating and conveying shovels which are suspended and towed [52] U.S. 37/57, 37/59, 37/71, along g g trajectory, the p p comprising three cylinders arranged for being filled with the dredged material and pumping it in sequence by means of compressed air cyclically fed to the cylinders under the control of a distributor, each cylinder being connected to a corresponding dredging shovel having a front cutting edge, which in turn is provided with 4 8 ws 6 l ZDW O 6 E9 1 959 2 ,8 3 3 2 n m i .fl "W W Wh .c r a .e S m en e .mF UN 55 [56] References Cited UNITED STATES PATENTS cutting knives inclined forwardly and downwardly so as to sink in the bed being dredged.

216,06] 6/1879 37/57 ux 1.097.722 5/1914 37 55 4 Claims, 9 Drawing Figures PAIENTEDomzzwu sum 10! 1 SUBMERSIBLE DREDGING PUMP AND SHOVEL ARRANGEMENT WITH SUSPENSION AND TOWING MEANS THEREFOR This invention relates to a dredging plant arranged for mounting on watercraft, and in particular relates to improvements both in the type of dredging shovels and in their disposition.

Dredging plants of the type in which a watercraft tows a submerged pump-dredging shovel assembly are known; the disintegrating and conveying shovels partially sink into the bed to be dragged and the material which thus penetrates into the shovels fills the chambers or cylinders of a submerged pneumatic pump in sequence through suitable ducts, these cylinders being successively fed with compressed air which empties them in sequence.

The very viscous semisolid material from the cylinders passes into a flow pipe which for example discharges into a lighter or constitutes the upstream section of a conveyor system for conveying to a distance.

The disintegrating and conveying shovels usually used are of the single type provided with a horizontal cutting edge arranged for partially sinking into the bed to be dredged, and teeth and cutting bars associated with the said horizontal edge are provided for disintegrating the material into which the cutting edge sinks so that said material reduced into pieces penetrates into the shovel and from here, in the form of a more or less dense pulp, flows through the ducts which connect the shovel to the pneumatic pump cylinders in order to fill the cylinders in sequence. In some cases, particularly when the bed to be dredged is of a clay or otherwise compact nature, considerable difficulties arise in dragging a single shovel, which can attain a width of some metres, while at the same time maintaining the depth of penetration, the speed of dredging, the efficiency of dredging and the operating costs of the plant at advantageous levels.

A further disadvantage, especially if the depth of penetration is not sufficient, is that the pulp which enters the cylinders of the submerged pneumatic pump is much less dense; in other words much more water is pumped, with consequent wastage of energy.

A further problem which has not been resolved up to the present time is that of dredging thin incoherent bed layers. Also in this case the single shovel used up to now works in practice much below its full capacity, because of which a very high percentage of water is pumped together with the dredged material, this water tending to penetrate inside the pump body from the top part of the shovel. 7

It has now been found, and constitutes the main object of the present invention,'that the problems and disadvantages briefly mentioned heretofore are completely eliminated by a dredging plant of the type comprising a submerged pump-disintegrating and conveying shovel assembly, and a rig arranged to support said submerged assembly at an adjustable depth and to move it along a dredging trajectory, characterised in that said pneumatic pump comprises three chambers or cylinders arranged to pump by compressed air the dredged material which periodically fills them, each cylinder being connected to a corresponding single disintegrating conveying shovel, comprising a toothed cutting edge arranged to engage with the bed to be dredged, and a plurality of vertical bars with cutting edges, arranged to disintegrate the material engaged by said cutting edge and reduce it to dimensions defined by the distances between the bars, the three shovels being disposed in plan at the vertices of a triangle and spaced in such a manner as to dredge the entire width defined by the two front shovels. In a particularly preferred embodiment, each shovel consists of two plates, which are slightly inclined to a horizontal plane and diverge at the forward ends thereof, defining the height of the shovel, of substantial rhomboidal profile, the two rear sides of the two plates being closed by plates which define a receiving and conveying cavity for the dredged material, which is in its turn connected by the connection piece to the inlet of the corresponding cylinder of the pneumatic pump, and the two front ends being connected by said vertical bars with front cutting edges, which in their turn are inclined towards the inside of the shovel starting from the upper plate and terminating in teeth facing upwards which project from the front converging edges of the front plate, constituting said toothed cutting edge, said vertical bars being in their turn connected by horizontal bars also comprising a front cutting edge, which together with the vertical bars form meshes for limiting the maximum size of material which enters into the said receiving and conveying cavity. In a particular embodiment of the shovel heretofore described, cutting bars or knives comprising at their ends a tooth which sinks into the bed to be dredged project downwards from the front converging edges of the lower plate, so helping to prevent the shovel from disengaging from the bed when it is dragged. I

In a further embodiment, useful when the layer to be dragged is of small thickness, each shovel as heretofore described in partially obscured, starting from the upper plate, to a height such that the front working surface of the shovel which remains after obscuring corresponds to the thickness of the layer to be dragged, this obscuring being obtained by means of a plate applied on the outside of said vertical bars.

In a further embodiment, useful when a thin layer 0 incoherent material without compactness has to be dragged on a bed, a plant is provided according to the present invention in which the individual shovels are formed from the said plates and the lower plate comprises a front edge inclined downwards which engages with the bed by sinking into it.

These and further aspects and advantages of the present invention will be evident from the following description given by way of non-limiting example with reference to the accompanying drawings in which:

FIG. 1 is a diagrammatic general view of the plant according to the present invention;

FIG. 2 is a perspective view of the pumpdisintegrating shovel assembly;

FIG. 3 is a plan view from above of the assembly of FIG. 2;

FIG. 4 is a partial lateral view of a cylinder of the pump and of the relative shovel;

FIG. 5 is a section on the line V-V of FIG. 4;

FIGS. 6 and 7 are views analogous to those of FIGS. 2 and 4 of a further embodiment; and

FIGS. 8 and 9 are views analogous to FIGS. 4 and 5 of a further embodiment of the present invention.

Considering firstly FIGS. 1, 2 and 3, these show a dredging plant comprising a watercraft 20, provided with dragging drive means (not shown, and on which is mounted a rig 21 from the rear of which a submerged pump-disintegrating shovel assembly 22 is suspended by means of cables. On the watercraft there are also mounted the motor-driven compressor and-distributor for the submerged assembly, and a pipe 25 provides for conveying the dredged and pumped material.

With reference to FIGS. 2 and 3, the submerged pump-dredging shovel assembly 22 comprises three pumping cylinders 26 constructed and operating in accordance with well known techniques, in particular as described in previous patents, such as U.S. Pat. No. 3,624,933 by the same applicant, (held together by structural elements 27) and each having an inlet aperture 29 for the material dredged by the shovels 28 (described hereinafter in detail), and a discharge duct 30 which extends inside to a short distance from the bottom of the pump body, the three ducts 30 joining together into a single conveying pipe or header 25.

The appropriate valves for controlling the inlet and outlet of the dredged material are provided inside the cylinders 26, and the cylinders 26 are connected to the compressed air distributor by way of the apertures 31 and flexible pipes 32.

As clearly indicated, with each cylinder 26 there is associated a disintegrating and conveying shovel 28. Each shovel 28 comprises two plates 33 and 34, which are slightly inclined to a horizontal plane and diverge at the forward ends thereof, of approximately rhomboidal profile, of which the rear sides which converge at the rear vertex are joined by lateral plates 35, which with the horizontal plates 33 and 34 define a receiving and conveying cavity 36 which, by way of a connection piece 37, communicates directly with the inlet aperture 29 of the respective pumping cylinder 26.

Joining bars 38 for the plates are rigidly fixed to the front, i.e. at the two front converging sides of the plates 33 and 34, these bars (as clearly shown in FIGS. 4 and having a front cutting edge 39 and being inclined towards the inside of the shovel, starting from the upper plate 33. This is obtained in practice by making the lower plate 34 smaller than theplate 33. At the juncture between the bars 38 and lower plate 34 there are teeth 40 facing upwards, which in practice project upwards towards the outside of the lower plate 34. Finally the vertical bars 38 are intersected at suitable distances by horizontal bars 41 which also have a front cutting edge 42, and which together with the vertical bars 38 define meshes the purpose of which is to limit the maximum size of the dredged material which penetrates into the cavity 36 of the shovel 28 and avoid any possibility of obstructing and damaging the pumping cylinders 26.

the cylinder 26 to a bracket 46 on the upper plate 33.

Asstated the shovels 28 as described above have been found in practical tests to be particularly effective for dredging beds of clay or otherwise very compact type, for which the single shovels of the previous art were not very effective and required the use of very powerful dragging members. The particular disposition of the shovels 28, which is clearly shown in FIG. 3, must also be emphasised, in which the rear shovel of the assembly which is dragged in the direction of the arrow 47 is partially superimposed on the paths already dredged by the two front shovels.

With reference to the embodiment shown in FIGS. 6 and 7, these show the modified shovel for dredging beds in which the thickness of the layer to be removed is very small. In this case the shovel of the embodiment shown in the previous figures is obscured, starting from the upper plate 33, by plates 48, preferably removable, which extend to such a level as to leave a part of the frontal area of the shovel corresponding to the height of the layer to be dredged free and active. In this manner large quantities of water are prevented from entering the pumping cylinders through the upper part of the shovel, which in addition to strongly diluting the dredged material would lead to a wastage of power, for example in terms of compressed air used for pumping.

Finally FIGS. 8 and 9 show a further modification in which the individual shovels 128 are used for removing from the bed a thin layer of substantially incoherent material.

In this case each shovel 128 is formed from two horizontal plates 133, 134 of substantially trapezoidal shape, joined laterally by vertical plates 135, forming the collecting and conveying chamber for the dredged material, which communicates by way of the connection piece 137 with the bottom of the pneumatic pumping cylinder 126. The strengthening tie bar mechanically connects the bottom of the cylinder 126 to the bracket 146 provided on the upper plate 133. It can be seen that in order to improve the action of the shovel and ensure an effect analogous with that of the knives 43 of the first described embodiment, the front edge 150 of the lower plate 134 is inclined downwards.

The invention has been described in relation to some preferred embodiments, but it is clear that conceptually and mechanically equivalent modifications and variations are possible without leaving the scope of the inventive idea. It should also be noted that in the description given heretofore neither the submerged pump nor the auxiliary equipment mounted on the watercraft have been examined in detail, as they represent mechanisms and apparatus well known in the prior art. Finally, although specific reference has been made to a dredging plant mounted on a watercraft, the submerged pumpdredging shovel assembly could equally be associated with a suspension apparatus mounted on a vehicle mobile along the bank of the bed to be dredged.

What is claimed is:

l. A dredging plant of the type comprising a submerged pump disintegrating and conveying shovel assembly, and a rig arranged to support said submerged assembly at an adjustable depth and to move it along a dredging trajectory, in which said submerged pump comprises three cylinders arranged for filling with the dredged material and to pump the dredged material which periodically fills them in sequence by means of compressed air supplied to the cylinders from a compressor by way of a distributor, wherein each of said cylinders is connected to a corresponding dredging shovel having a front cutting edge and formed from two plates which are slightly inclined to a horizontal plane and diverge forwardly from each other and are connected by lateral plates so as to define a cavity for collecting the dredged material, the lower of the two plates being provided with cutting means which are inclined downwards and have a tendency to sink into the bed which is dredged.

2. A plant as claimed in claim 1, in which in each shovel the two said slightly inclined plates have a substantially rhomboidal shape with sides converging to the rear and sides converging to the front, of which said lateral plates connect the sides converging to the rear, whereas the sides converging-to the front are joined rigidly by bars inclined towards the inside of the shovel starting from the upper plate and having a front cutting edge, said bars being rigid, at the juncture with the lower plate, with teeth projecting upwards and out- 4. A plant as claimed in claim 3, in which said cavity of the shovels may be partially closed by removable obscuring plates of such a height as to leave free a working surface of the shovel corresponding substantially to the thickness of the layer to be dredged.

Patent No. 3,842,521 Dated October 22, 1974 Inventor s) GIOVANNI FALD I It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the title page after item [21] insert the following:

[30] FOREIGN APPLICATION PRIORITY DATA March 20, 1972 Italy ..22115 A/72 Signed and sealed this 22nd day of April 1975.

s are at test 3 C i-LQRSIALL DAN RUE? C. MASON Commissioner of Patents attesting Officer and Trademarks FORM PC4050 (1069) uscoMM-Dc 60376-P69 1* ".5. GOVERNMENT PRINTING OFFICE Ii O-fiGl-BS. 

1. A dredging plant of the type comprising a submerged pump disintegrating and conveying shovel assembly, and a rig arranged to support said submerged assembly at an adjustable depth and to move it along a dredging trajectory, in which said submerged pump comprises three cylinders arranged for filling with the dredged material and to pump the dredged material which periodically fills them in sequence by means of compressed air supplied to the cylinders from a compressor by way of a distributor, wherein each of said cylinders is connected to a corresponding dredging shovel having a front cutting edge and formed from two plates which are slightly inclined to a horizontal plane and diverge forwardly from each other and are connected by lateral plates so as to define a cavity for collecting the dredged material, the lower of the two plates being provided with cutting means which are inclined downwards and have a tendency to sink into the bed which is dredged.
 2. A plant as claimed in claim 1, in which in each shovel the two said slightly inclined plates have a substantially rhomboidal shape with sides converging to the rear and sides converging to the front, of which said lateral plates connect the sides converging to the rear, whereas the sides converging to the front are joined rigidly by bars inclined towards the inside of the shovel starting from the upper plate and having a front cutting edge, said bars being rigid, at the juncture with the lower plate, with teeth projecting upwards and outwards from the lower plate so as to project from its external perimeter, there being also provided horizontal bars having a front cutting edge which interconnect said vertical bars at distances which are suitably chosen in accordance with the maximum size of material permitted in said cavity internal to the shovel.
 3. A plant as claimed in claim 2, in which from the bottom of said lower plate there project knives inclined downwards and terminating in a tooth facing upwards.
 4. A plant as claimed in claim 3, in which said caviTy of the shovels may be partially closed by removable obscuring plates of such a height as to leave free a working surface of the shovel corresponding substantially to the thickness of the layer to be dredged. 